This invention relates to the stripping or removal of concrete forms from the roadbed of bridges during the construction of the bridge and more particularly to apparatus supported on and driven along the surface of poured concrete roadbed sections of a bridge, the apparatus including support members disposed beneath the roadbed for carrying apparatus for removing the forms and which support members may move transversely to clear the vertical piers which support the bridge.
In the construction of concrete roadbed bridges concrete pouring forms are disposed adjacent precast longitudinally extending beams carried by transversely extending pier caps or bents supported on piles or columns. For multiple span bridges, i.e., bridges having super-structures spanning a number of longitudinally spaced apart piers, the roadbed is poured in sections, each section generally comprising the portion of the bridge between adjacent pier caps. After the concrete has begun to cure, the concrete forms from a first section are removed or stripped and utilized for the pouring of a subsequent section.
The conventional stripping of the concrete pouring forms can be a time consuming procedure increasing the bridge construction time and cost. For multiple span bridges the forms are stripped, disassembled and dropped or hoisted down onto a barge in the water below the bridge, or onto the ground in the case of bridge sections overlying the ground. These forms must thereafter be reassembled when used at a subsequent bridge section. If the height of the bridge above the water or ground is not too great, scissors jacks may be disposed on the barge or ground so that the forms may be stripped without being disassembled.
The only known apparatus in the prior art which attempted to provide an aid to the stripping of the bridge forms was a structure proposed some 25 to 30 years ago known as the "Triad Stripping Buggy" which spanned the width of the bridge but was only some 8 to 10 feet in width. In that apparatus a support structure was positioned on the concrete roadbed and supported framing above the roadbed, the framing having spaced vertically depending members at the transverse ends thereof and these members carried decking on which workmen could stand for accessing and stripping the forms. The supporting structure was pushed or pulled by a truck or tractor or the like along the roadbed and when it reached the vicinity of the pier, each half of the decking could be rolled outwardly and be rotated 90.degree. to be free of the pier cap to permit the structure to be moved to the next section. Since a motorized vehicle was required for moving thestructure longitudinally, the vehicle was required to ride along a finished portion of the roadbed, generally before it was fully cured if excessive delays were not to be encountered, or if the bridge was of a relatively short span, a cable on the vehicle could be used to pull the structure from the unfinished end. Additionally, this arrangement could not be used where the distance between the piers was small relative to the width of the bridge lest the decking when rotated would contact the adjacent pier cap or be rolled outwardly to a point where the bending forces due to the cantilever effect were excessive. Moreover, the apparatus could not strip forms which run longitudinally because of its small width, but could be used as a work platform for workmen to loosen the form as the deck was moved longitudinally and the forms still had to be dropped. Accordingly, this apparatus did not find wide acceptance and its use appears to have been abandoned.